Hydraulic-setting adhesives are widely used in the construction industry. For example they can be used as adhesives for adhering ceramic tiles. The adhesives mainly contain inorganic hydraulic-setting binder, such as cements, and fillers, such as quartz and/or carbonate-containing raw materials. Such hydraulic-setting adhesives can be provided in the form of a polymer-containing mortar composition, into which additives can be added for improving the technical and physical properties of an adhesive. For example, a water retention agent, particularly cellulose ethers, can be added into such a hydraulic setting adhesive to improve thickening(consistency) and increase their water retention capacity.
Long open time and short setting time are desired as important properties in evaluating workability of a hydraulic setting adhesive as an adhesive in construction industry. In the prior art, different retarders are used to improve open time of a hydraulic setting adhesive.
JP2000128617 teaches a composition that contains hydroxypropylmethyl cellulose, seaweed-derived water-soluble polymers, and/or set retarders. Such polymers include carrageenan, alginic acid, sodium alginate, etc. Hydroxybenzene, phenolic acid, carboxylic acid, oxycarboxylic acid, aminocarboxylic acid, their salts, silicofluoride, phosphate, borate, etc., may be added as a setting retarder. The composition has a long open time and can be applied onto large areas in one batch.
US20060169183A1 teaches a hydraulically setting mortar composition containing at least one cellulose ether and at least one setting retarder which might be polyhydroxy compounds, phosphates, water-soluble silicofluorides, boric acid and salt thereof, carboxylic acids and salts thereof, carboxyl group-containing polymers, etc.
US20080196629A1 teaches a self-leveling composition containing cement, fillers, water-reducing agents, defoamers and a setting retarder that can be hydroxycarboxylic acids, such as gluconic acid, citric acid and glucoheptonic acid, inorganic salts thereof, sacchardies, and boric acid.
The prior-art adhesive compositions as mentioned above achieves a long open time with the help of retarders, but at the same time the retarders lead to a significant delay in hydraulic setting kinetics. Such impact on setting brings economic drawbacks due to a delayed construction progress. Other disadvantages include changed water loads and low adhesion strength.
The present inventors have sought to solve the problem of providing a hydraulic-setting adhesive to achieve a long open time without deteriorating other properties, especially setting time.